RAR archive of 5.35 MB for the Biostar H310MHD PRO motherboard, version 6.x, with 523 in the name possibly marking a firmware build. The index lists the brand as ECS. Contents are not specified, but the size suggests a BIOS image or related files. If it holds a dump, back up the existing SPI chip before programming, verify the board version on the PCB is 6.x, and check that the image size matches the flash chip capacity.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @vinafix_bios. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
7-ZipWinRARThe Unarchiver (macOS)